Re: Sims 3 family relationships

Without a mod, it's not possible to add any relationships of Sims already in town.

What you could do, is start over (if you haven't played too long)

- Take your Sim with the dresser/mirror/... to CAS

- Export the Sim 

- Repeat for all your Sims

- Close the game

- Start the launcher

- In your Upload Tab you should now find all your Sims, install them

- Start the game

- Go to CAS. The Sims you made should now be in the Premade Sims Bin

- Add them to your new family and set the relationsship.

All progress you made with them will be gone though.